Left picture: The diagnosis is an infected thyroglossal duct cyst which has already been incised once due to an abscess.
Right picture: The diagnosis in this case is a median cleft neck. This congenital malformation consists of a median indentation of poor quality skin, of a superficial sinus, and of residuals of fibroma or chondroma.

Both patients have a chin pit, and in the midline of the neck a reddened zone of skin.
Left picture: The reddened zone lies over a transverse-oval mass above the isthmus of the thyroid gland; the mass is cystic on palpation.
Right picture: The reddened zone has a longitudinal shape, is somewhat wet and reveals no mass underneath the lesion except for a small nodule at the cranial end. Both pathologies give rise to the idea of a chronic infection.
Left picture: Here, exceptionally, a small scar is visible.